JPH0712042A - Two-stage pump turbine and its exhaust operation method - Google Patents

Abstract

(57) [Summary] [Purpose] To reliably prevent the low-pressure stage runner chamber from being filled with water before the high-pressure stage runner chamber is filled with water. [Structure] During the exhaust operation, water is injected into the outer periphery of the low pressure stage runner while the water injection pipe 34 is in the fully closed state of the low pressure stage movable guide vane 8. When the detector 34 detects that the flow passage 33 between the outer peripheral portion of the low pressure stage runner and the movable guide vane of the low pressure stage is filled with the water from the water injection pipe 34, the high pressure via the high pressure stage exhaust passage 15 The air in the stage runner chamber 6 is exhausted. Along with this exhaust, the high-pressure stage water supply pipe 24 introduces the water in the suction pipe 13 into the high-pressure stage runner chamber 6 to fill it. After this, the air in the low pressure stage runner chamber 12 is exhausted through the low pressure stage exhaust passage 16, and the water in the suction pipe 13 fills the low pressure stage runner chamber 12 with this exhaust.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-stage pump turbine and its exhaust operation method, and more particularly, to each runner chamber when shifting from a water-pushing idle operation to a pumping operation or a power-generating operation at the time of pump startup or phase-shifting operation. The present invention relates to an exhaust device and an exhaust operation method for a two-stage pump turbine that exhausts the exhaust gas.

[0002]

2. Description of the Related Art Generally, in a turbine or a pump turbine, compressed air is runner after fully closing a movable guide vane and an inlet valve in a phasing operation for the purpose of adjusting the frequency of an electric system or in the case of starting the pump. In the state where the water surface of the runner chamber is pushed down after being introduced into the room, the runner idles while the surface of the runner is idle. After the idling operation to push down the water surface, the compressed air in the runner chamber is exhausted by the exhaust operation and water is supplied to it.
Shift to normal operation. In this exhaust operation, in a two-stage pump turbine having a high pressure runner and a low pressure runner, it is necessary to exhaust the high pressure stage and the low pressure stage in a predetermined order.

FIG. 7 shows a two-stage pump turbine developed by the applicant of the present invention capable of exhausting a high-pressure stage and a low-pressure stage in a predetermined order during an exhaust operation. The flow passage leading to the casing 1 is shown in FIG. A high-pressure stage movable guide vane 2 and a high-pressure stage runner 3 are respectively arranged, and the high-pressure stage runner 3 is located in a high-pressure stage runner chamber 6 formed by an upper cover 4 and a lower cover 5. The flow path from the high-pressure stage runner chamber 6 is connected to the low-pressure stage by the return flow path 7, and the low-pressure stage is provided with a movable guide vane 8 and a low-pressure stage runner 9, respectively. The low pressure stage runner 9 is arranged in a low pressure stage runner chamber 12 formed by an upper cover 10 and a lower cover 11, and a suction pipe 13 is connected to the low pressure stage runner chamber 12.

A main shaft 14 to which the high-pressure stage runner 3 and the low-pressure stage runner 9 are fixed, passes through the suction pipe 13,
An exhaust passage 15 for the high-pressure stage and an exhaust passage 16 for the low-pressure stage are bored in the main shaft 14, and the exhaust passage 15 for the high-pressure stage communicates the high-pressure stage runner chamber 6 with the high-pressure stage exhaust chamber 17 to form the low-pressure stage. The exhaust passage 16 connects the low pressure stage runner chamber 12 to the low pressure stage exhaust chamber 18. The high-pressure stage exhaust chamber 17 and the low-pressure stage exhaust chamber 18 have a high-pressure stage exhaust pipe 19 with one end open to the outside.
And the low-pressure stage exhaust pipe 20 are connected, and the high-pressure stage exhaust pipe 19 and the low-pressure stage exhaust pipe 20 are provided with exhaust control valves 21 and 22, respectively.

A high pressure stage runner chamber 6 and a low pressure stage runner chamber 12,
Specifically, the low-pressure stage runner back pressure chamber 12 a is in communication with each other via an inter-stage seal 23. The return flow path 7 and the suction pipe 13 are communicated with each other by a water injection drainage pipe 24, and a water injection control valve 25 is installed in the water injection drainage pipe 24.

An intermediate seal 26 is installed at the back of the high pressure stage runner, and a back pressure chamber 27 inside the high pressure stage on the inner peripheral side of the intermediate seal 26 is connected to the suction pipe 13 by a balance pipe 28. . By omitting the intermediate seal at the back of the low pressure stage runner, effective thrust control can be performed during normal operation. This two-stage pump turbine
It is necessary to exhaust the high pressure stage runner chamber 6 first to establish the water pressure and then exhaust the low pressure stage runner chamber 12 to establish the water pressure.

That is, when the water pressure is established first from the high pressure stage runner chamber 6, the thrusts a and b acting on the high pressure stage runner 3 are always balanced as shown in FIG. Since the outlet pressure of the runner 3 is almost the same as the pressure of the suction pipe 13, both thrusts c and d are balanced.
Therefore, when the water pressure is established first from the high pressure stage runner chamber 6, excessive axial thrust does not occur in the main shaft 14. However, if water pressure is established first from the low-pressure stage runner chamber 12, unequal thrusts e, f, g, and h act on the low-pressure stage runner 9, so that an excessive downward axial thrust is applied to the main shaft 14. Will occur.

Therefore, during the exhaust operation, first, the control valve 21
The control valve 25 and the control valve 25 are opened to exhaust the air in the high pressure stage runner chamber 6 through the high pressure stage exhaust passage 15 and the water in the suction pipe 13 to the high pressure stage runner chamber 6 through the water injection and drain pipe 24. Fill with water. Next, the control valve 22 is opened, and the air in the low pressure stage runner chamber 12 is exhausted through the low pressure stage exhaust passage 16, thereby filling the low pressure stage runner chamber 12 with the water in the suction pipe 13. Thus, the high pressure stage and low pressure stage runner chambers 6, 1
After 2 is sequentially filled with water, the guide vanes 2 and 8 of the high pressure stage and the low pressure stage are opened to shift to the normal operation.

[0009]

However, in the above-described two-stage pump turbine developed by the present applicant, the interstage seal blocks the flow of water but does not block the flow of air flow, so that the low-pressure stage runner chamber However, there is a problem that the main shaft is filled with water first and excessive downward thrust is generated in the main shaft to burn the thrust bearing. More specifically, the high-pressure stage runner chamber and the low-pressure stage runner chamber communicate with each other through an interstage seal, which has a sealing effect on water flow but a sealing effect on air flow. Since the air in the high pressure stage runner chamber is exhausted through the high pressure stage exhaust passage, the compressed air in the low pressure stage runner chamber leaks to the high pressure stage runner chamber through the interstage seal, and The low-pressure stage runner chamber will be refilled prior to refilling.

Therefore, an object of the invention described in claims 1 and 4 of the present application is to provide a two-stage pump turbine capable of reliably preventing the low-pressure stage runner chamber from being filled with water before the high-pressure stage runner chamber is filled with water. It is to provide an exhaust operation method. Also,
An object of the invention as set forth in claim 5 of the present application is to prevent an excessive axial thrust from being generated in the main shaft even when the low pressure stage runner chamber is filled with water before the high pressure stage runner chamber is filled with water. It is to provide a two-stage pump turbine that can be prevented.

[0011]

In order to achieve this object, a first aspect of the present invention provides a return flow passage that connects a high pressure stage flow passage and a low pressure stage flow passage, the high pressure stage and the above high pressure stage. The runners and movable guide vanes installed in each of the low-pressure stages, and the exhaust passage for the high-pressure stage that communicates the high-pressure stage runner chamber and the low-pressure stage runner chamber to the outside during the exhaust operation that shifts from the water-push down idle operation to the normal operation And a low-pressure stage exhaust passage, a high-pressure stage water supply pipe that communicates the suction pipe and the return flow passage during the exhaust operation to introduce the water in the suction pipe into the high-pressure stage runner chamber, and the low-pressure stage during the exhaust operation. The water injection pipe for injecting water into the outer peripheral portion of the low pressure stage in the fully closed state of the movable guide vane, and the flow path between the outer peripheral portion of the low pressure stage runner and the movable guide vane of the low pressure stage is the water injection pipe. Filled with water from It is characterized in that it comprises a detecting means for detecting. In such a configuration, it is preferable that one end of the water injection pipe is opened to a flow passage between the outer peripheral portion of the low pressure stage runner chamber and the inside of the movable guide vane of the low pressure stage.

It is desirable that one end of the water injection pipe is opened to one of the runner side pressure chamber and the runner back pressure chamber of the low pressure stage runner. According to a fourth aspect of the present invention, there is provided a return flow passage communicating the high pressure stage flow passage and the low pressure stage flow passage, a runner and a movable guide vane installed in each of the high pressure stage and the low pressure stage, and a high pressure state. In the exhaust operation method of a two-stage pump turbine having a high-pressure stage exhaust passage and a low-pressure stage exhaust passage that respectively communicate the outside of the low-pressure stage runner chamber and the low-pressure stage runner chamber, in a fully closed state of the movable guide vanes of the low-pressure stage. In the first step of injecting water into the outer periphery of the low-pressure stage runner and in the step of detecting that the flow path between the outer periphery of the low-pressure stage runner and the movable guide vane of the low-pressure stage is filled with the water injection. Step 2, a third step of exhausting the air in the high-pressure stage runner chamber after the detection through the high-pressure stage exhaust passage, and with the exhaust of the third step, the suction pipe and the For the high pressure stage water supply pipe that communicates with the high pressure stage runner chamber A fourth step of introducing the water in the suction pipe into the high pressure stage runner chamber, and after the fourth step, exhausting the air in the low pressure stage runner chamber through the low pressure stage exhaust passage A fifth step of introducing water in the pipe into the low-pressure stage runner chamber, and a sixth step of slightly opening the movable guide vanes of the low-pressure stage after the fifth step and thereafter closing the high-pressure stage feed pipe. And a process.

According to a fifth aspect of the present invention, there is provided a return flow passage communicating the high pressure stage flow passage and the low pressure stage flow passage, and runners and movable guide vanes installed in each of the high pressure stage and the low pressure stage. And the exhaust passage for the high-pressure stage and the exhaust passage for the low-pressure stage that communicate the high-pressure stage runner chamber and the low-pressure stage runner chamber to the outside during the exhaust operation that shifts from the water-push down idle operation to the normal operation, and the suction during the exhaust operation. A high-pressure stage water supply pipe that connects the pipe and the return flow passage and introduces the water in the suction pipe into the high-pressure stage runner chamber, and the high-pressure stage runner chamber installed in the side pressure chamber or the back pressure chamber of the high-pressure stage runner. High pressure stage water pressure detection means for detecting that the cutoff water pressure has been reached due to completion of filling, and that the low pressure stage runner chamber installed in the side pressure chamber or the back pressure chamber of the low pressure stage runner has reached the cutoff water pressure due to completion of filling Low pressure water pressure detection Means and said low-pressure water pressure detecting means during the pumping operation is characterized in that it comprises a control device for stopping the main engine when it detects the deadline pressure earlier than the high-pressure stage the water pressure detecting means.

[0014]

The operation of the invention described in claim 1 is as follows. During exhaust operation, water is injected into the outer periphery of the low-pressure stage runner with the water injection pipe fully closed when the low-pressure stage movable guide vane is used, and the detection means is used between the outer periphery of the low-pressure stage runner and the low-pressure stage movable guide vane. It is detected that the flow path of is filled with the water from the water injection pipe. In response to this detection, the air in the high pressure stage runner chamber is exhausted through the high pressure stage exhaust passage. With this exhaust, the high-pressure stage water supply pipe introduces the water in the suction pipe into the high-pressure stage runner chamber to fill the high-pressure stage runner chamber. After this, the air in the low pressure stage runner chamber is exhausted through the low pressure stage exhaust passage, and along with this exhaust, the water in the suction pipe fills the low pressure stage runner chamber.
When the flow path between the outer peripheral portion of the low-pressure stage runner and the movable guide vane of the low-pressure stage is filled with water from the water injection pipe, air communication between the low-pressure stage runner chamber and the high-pressure stage runner chamber via the interstage seal is established. Since the air is shut off, the air in the low pressure stage runner chamber is prevented from leaking to the high pressure stage runner chamber through the interstage seal when the high pressure stage runner chamber is exhausted.

The operation of the invention described in claim 4 is as follows. Water was injected into the outer periphery of the low-pressure stage runner when the low-pressure stage movable guide vane was fully closed, and this water injection filled the flow path between the low-pressure stage runner outer periphery and the low-pressure stage movable guide vane. When this is detected, the air in the high pressure stage runner chamber is exhausted through the high pressure stage exhaust passage, and along with this exhaust, the water in the suction pipe is introduced into the high pressure stage runner chamber through the high pressure stage water supply pipe. It Thereafter, when the air in the low pressure stage runner chamber is exhausted through the low pressure stage exhaust passage, water in the suction pipe is introduced into the low pressure stage runner chamber accordingly.
After this, the movable guide vanes of the low pressure stage are slightly opened, and then the high pressure stage water supply pipe is closed.

The operation of the invention described in claim 5 is as follows. When the low-pressure stage water pressure detection unit detects the cutoff water pressure before the high-pressure stage water pressure detection unit during the exhaust operation, the low-pressure stage runner chamber is filled faster than the high-pressure stage runner chamber is filled up due to some cause. Since it is completed and excessive thrust is generated in the main shaft, the control device stops the main engine.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a two-stage pump turbine according to the present invention will be described below with reference to FIGS. 1 to 6 in which the same parts as those in FIGS. FIG. 1 shows a first embodiment of the present invention. A movable guide vane 2 of a high pressure stage and a high pressure stage runner 3 are respectively arranged in a flow path leading to a casing 1, and the high pressure stage runner 3 has an upper cover. 4 and the lower cover 5 are located in a high pressure stage runner chamber 6.

The flow path from the high pressure stage runner chamber 6 is the return flow path 7
A return vane 7a is arranged in the return passage 7 by being connected to the low pressure stage. A low-pressure stage movable guide vane 8 and a low-pressure stage runner 9 are installed in the low-pressure stage, and the low-pressure stage movable guide vane 8 and the high-pressure stage movable guide vane 2 are controlled to open and close by independent operating mechanisms. The low-pressure stage runner 9 is arranged in a low-pressure stage runner chamber 12 formed by an upper cover 10 and a lower cover 11, and an elbow-shaped suction pipe 13 is connected to the low-pressure stage runner chamber 12.

The main shaft 14 to which the high-pressure stage runner 3 and the low-pressure stage runner 9 are respectively fixed, penetrates the suction pipe 13,
An exhaust passage 15 for the high-pressure stage and an exhaust passage 16 for the low-pressure stage are bored in the main shaft 14, and the exhaust passage 15 for the high-pressure stage communicates the high-pressure stage runner chamber 6 with the high-pressure stage exhaust chamber 17 to form the low-pressure stage. The exhaust passage 16 connects the low pressure stage runner chamber 12 to the low pressure stage exhaust chamber 18. The high pressure stage exhaust chamber 17 and the low pressure stage exhaust chamber 18 are sealed by a water sealing device 29 in order to prevent the high pressure water from the high pressure stage runner chamber 6 from flowing around during normal operation.

The high-pressure stage exhaust chamber 17 and the low-pressure stage exhaust chamber 18 are connected to a high-pressure stage exhaust pipe 19 and a low-pressure stage exhaust pipe 20, respectively, one end of which is open to the outside. Exhaust control valves 21, 2 are provided in the pipe 20.
2 are installed respectively. The high pressure stage runner chamber 6 and the low pressure stage runner chamber 12, specifically, the low pressure stage runner back pressure chamber 12 a are communicated with each other via an interstage seal 23. The return flow path 7 and the suction pipe 13 are communicated with each other by a water injection drainage pipe 24 that functions as a high-pressure stage water supply pipe, and a water injection control valve 25 is installed in the water injection drainage pipe 24. The water injection control valve 25 is closed during normal operation.

An intermediate seal 26 is installed at the back of the high-pressure stage runner, and a back pressure chamber 27 inside the high-pressure stage on the inner peripheral side of the intermediate seal 26 communicates with the suction pipe 13 by a balance pipe 28. . The branch pipes 30a and 30b of the air supply pipe 30 are connected to the upper portion of the suction pipe 13 and the return passage 7, and the air supply control valve 3 is connected to these branch pipes 30a and 30b.
1, 32 are installed.

In the outer peripheral flow passage 33 between the outer peripheral portion of the low pressure stage runner chamber 12 and the inner side of the low pressure stage guide vane 8, the water injection pipe 3 is provided.
4 is connected to one end, and the other end of the water injection pipe 34 is connected to an external high-pressure water source (not shown). A water injection control valve 35 is installed in the water injection pipe 34, and an electrode type or pressure detection type detector 36 is installed in the outer peripheral flow path 33. In this detector 36, the flow path 33 is filled with water from the water injection pipe 34, and the low-pressure stage runner chamber 12 through the interstage seal 23 is inserted.
It is detected that the air communication between the high pressure runner chamber 6 and the high pressure stage runner chamber 6 is cut off.

A pressure relay 37 serving as a high-pressure stage water pressure detecting means is installed on the outer periphery of the runner in the high-pressure stage runner chamber 6, and this pressure relay 37 indicates that the high-pressure stage runner chamber 6 is completely filled with water, that is, high pressure. The priming water pressure on the outer periphery of the runner of the step runner chamber 6 is detected. Similarly, pressure relays 38 and 39, which serve as low-pressure stage water pressure detection means, are installed on the outer periphery of the runner in the low-pressure stage runner chamber 12.
8 detects the start of increase in water pressure in the flow path 33, and the pressure relay 3
9 indicates that the low pressure stage runner chamber 12 is completely filled with water, that is, the priming water pressure on the outer peripheral portion of the low pressure stage runner chamber 12 is detected.

Next, the operation of this embodiment will be described. In the case of the water turbine operation, the pressure water flowing from the casing 1 passes through the high pressure stage movable guide vanes 2 to rotationally drive the high pressure stage runners 3, and then the return passage 7 and the low pressure stage movable guide vanes 8 are provided.
The low pressure stage runner 9 is driven to rotate through the suction pipe 13
Drained from. In the case of the pump operation, the water flow pumped from the suction pipe 13 by the low pressure stage runner 9 is further pumped by the high pressure stage runner 3 through the water channel opposite to the case of the above-described turbine operation. In the case of idling operation with the water surface depressed,
The exhaust control valves 21 and 22 are closed, and the water injection control valve 25
With the movable guide vanes 2 and 8 of the high pressure stage and the low pressure stage fully closed, the air supply control valves 31, 3
2 is opened, and compressed air is blown from the air supply pipe 30 into the upper portion of the suction pipe 13 and the return passage 7. As shown in FIG. 2, the compressed air blown into the return passage 7 causes
The water in the high-pressure stage runner chamber 6 and the return flow path 7 is injected into the drainage pipe 2
It is pushed down into the suction pipe 13 via 4. Further, the compressed air blown into the upper portion of the suction pipe 13 pushes down the water in the upper portion of the suction pipe 13. After this, the air supply control valves 31, 32 are closed.

In this state, when the high-pressure stage runner 3 and the low-pressure stage runner 9 start idle in the pump direction and reach the rated speed, the motors are synchronously paralleled to the system. In the case of the exhaust operation, when an exhaust command is generated during the water surface downward idling operation, the water injection control valve 35 is opened, whereby high pressure water is injected from the water injection pipe 34 into the outer peripheral passage 33 of the low pressure stage runner chamber 12. It As shown in FIG. 3, the injected water accumulates on the outer peripheral side of the low pressure stage runner chamber 12 due to the centrifugal force of the low pressure stage runner 9 during idling, and forms a water curtain 40. The water curtain 40 blocks air communication between the low pressure stage runner chamber 12 and the high pressure stage runner chamber 6 via the interstage seal 23.

When the detector 36 detects the formation of the water curtain 40, it opens the exhaust control valve 21 to exhaust the air in the high pressure stage runner chamber 6 through the high pressure stage exhaust passage 15 and the exhaust pipe 19. . Depending on the exhaust of the high pressure stage runner chamber 6,
Since the pressure in the high pressure stage runner chamber 6 becomes lower than the pressure in the suction pipe 13, the water in the suction pipe 13 is introduced into the high pressure stage runner chamber 6 through the water injection drainage pipe 24. At this time, since the water curtain 40 is accumulated in the outer peripheral side flow passage 33 of the low pressure stage runner chamber 12 by the centrifugal force of the low pressure stage runner 9 as described above,
Even if the pressure of the low-pressure stage runner back pressure chamber 12a decreases due to the decrease of the pressure of the high-pressure stage runner chamber, the water curtain 40 is not destroyed, and the space between the low-pressure stage runner chamber 12 and the high-pressure stage runner chamber 6 is surely secured. The air is shut off to prevent the air in the low pressure stage runner chamber 12 from leaking to the high pressure stage runner chamber 6 through the interstage seal 23.

When the pressure relay 37 detects that the high pressure stage runner chamber 6 is completely filled with water, that is, the priming water pressure on the outer peripheral portion of the runner of the high pressure stage runner chamber 6, is detected.
Open. As a result, the air in the low-pressure stage runner chamber 12 is exhausted through the low-pressure stage exhaust passage 16, and the water level in the suction pipe 13 rises accordingly.
Replenishment of water begins. When the low pressure stage runner chamber 12 starts to be filled with water, the water pressure in the outer peripheral side flow passage 33 of the low pressure stage runner chamber 12 starts to rise, and the pressure relay 38 detects this rise in water pressure. When the pressure relay 38 detects an increase in water pressure, the low-pressure movable guide vane 8 is slightly opened, and then the water injection control valve 25 is closed.

The reason why the low pressure stage movable guide vane 8 is slightly opened before the water injection control valve 25 is closed is as follows. That is, if the water injection control valve 25 is closed while the low-pressure stage movable guide vane 8 remains closed, the return passage 7 becomes a vacuum due to the suction action of the high-pressure stage runner 3, so that the low-pressure stage movable guide This is prevented by opening the vane 8 slightly.

When the low pressure stage runner chamber 12 is completely filled with water, the pressure relay 39 detects this and closes both the exhaust control valve 21 and the exhaust control valve 22, and at the same time the high pressure stage movable guide vanes 2 and Open the low pressure stage movable guide vane 8. This starts the pump operation.

FIG. 4 shows a modification of the above embodiment. One end of the water injection pipe 34 opens into the runner side pressure chamber 12b located on the outer periphery of the low pressure stage runner chamber 12, and this runner side pressure chamber 12b is opened. High-strength water is introduced into the flow path 33 via the.
Other configurations are the same as those in FIG.

FIG. 5 shows another modification of the above embodiment, in which the detector 36 is installed in the runner back pressure chamber 12a located on the outer periphery of the low pressure stage runner chamber 12 to detect the formation of the water curtain 40. To do. FIG. 6 shows a second embodiment of the present invention, in which a pressure relay 37 serving as a high pressure stage water pressure detecting means is shown.
Detects that the high-pressure stage runner chamber 6 is completely filled with water, that is, the high-pressure stage priming water pressure on the outer periphery of the runner of the high-pressure stage runner chamber 6. Further, in the pressure relay 39, the low pressure stage runner chamber 12 is completely filled with water, that is, the low pressure stage runner chamber 12 is filled.
Detects the priming water pressure in the low-pressure stage on the outer periphery of the runner.
The detection output of the pressure relay 37 and the detection output of the pressure relay 39 are input to the control device 41, and when the detection output of the pressure relay 39 is input before the detection output of the pressure relay 37, the control device 41 That is, when the low pressure priming water pressure is established before the high pressure priming water pressure,
Stop the main engine. As described above, when the low pressure stage runner chamber 12 is filled with water and the water pressure is established before the high pressure stage runner chamber 6, the control device 41 determines this state and immediately stops the main engine. Generation of water thrust,
Also, it is possible to prevent the thrust bearing from being burned or the like.

[0032]

As is apparent from the above description, claim 1
According to the present invention described in (4) and (4), when the outer peripheral portion of the low-pressure stage runner is filled with water from the water injection pipe, the air in the low-pressure stage runner chamber is exhausted through the interstage seal when the high-pressure stage runner chamber is exhausted. As it is prevented from leaking into the runner room,
It is possible to reliably prevent the low-pressure stage runner chamber from being filled with water before the high-pressure stage runner chamber is filled with water, and to prevent an excessive axial thrust from being generated in the main shaft.

According to the fifth aspect of the present invention, during the exhaust operation, when the low pressure water pressure detecting means detects the cutoff water pressure before the high pressure water pressure detecting means, the main machine is stopped, so that the main shaft is excessively large. It is possible to prevent the thrust from being generated.

[Brief description of drawings]

FIG. 1 is a sectional view schematically showing a first embodiment of a two-stage pump turbine according to the present invention.

FIG. 2 is a cross-sectional view showing a water surface pushing-down operation state of the above embodiment.

FIG. 3 is a cross-sectional view showing a state at the start of the exhaust operation of the above embodiment.

FIG. 4 is a sectional view showing a modification of the above embodiment.

FIG. 5 is a sectional view showing another modified example of the above embodiment.

FIG. 6 is a sectional view schematically showing a second embodiment of a two-stage pump turbine according to the present invention.

FIG. 7 is a cross-sectional view showing a conventional water pump pushing operation state of a two-stage pump turbine.

FIG. 8 is an explanatory diagram showing the axial thrust force of a conventional two-stage pump turbine.

[Explanation of symbols]

 2 High-pressure movable guide vanes 3 High-pressure runners 6 High-pressure runner chambers 7 Return flow passage 8 Low-pressure movable guide vanes 9 Low-pressure runners 12 Low-pressure runner chambers 13 Suction pipes 15 Exhaust passages for high-pressure stages 16 Exhaust for low-pressure stages Channel 24 Water injection drainage pipe (high pressure stage water supply pipe) 33 Low pressure stage runner outer peripheral flow path 34 Water injection pipe 36 Detecting means 41 Control device

Front page continued (72) Inventor Teiichi Umeda 1 Higashishin-cho, Higashi-ku, Nagoya, Aichi Chubu Electric Power Co., Inc. (72) Inventor Toshifumi Kurokawa 2-4, Suehiro-cho, Tsurumi-ku, Yokohama-shi, Kanagawa Company Toshiba Keihin Office (72) Inventor Hiroshi Takigawa 2-4 Suehiro-cho, Tsurumi-ku, Yokohama-shi, Kanagawa Toshiba Keihin Office

Claims (5)

[Claims] 1. A return flow passage communicating between a high pressure stage flow passage and a low pressure stage flow passage, runners and movable guide vanes installed in each of the high pressure stage and the low pressure stage, and from a water surface pushing idle operation. An exhaust passage for the high-pressure stage and an exhaust passage for the low-pressure stage that communicate the high-pressure stage runner chamber and the low-pressure stage runner chamber to the outside during the exhaust operation that shifts to normal operation, respectively, and the suction pipe and the return passage during the exhaust operation. Injecting water into the outer periphery of the low pressure stage runner with the high pressure stage water supply pipe for introducing the water in the suction pipe into the high pressure stage runner chamber and the movable guide vane of the low pressure stage fully closed during the exhaust operation. And a detection unit that detects that the flow path between the outer peripheral portion of the low-pressure stage runner and the movable guide vane of the low-pressure stage is filled with water from the water injection pipe. A two-stage pump turbine. 2. The water injection pipe according to claim 1, wherein one end of the water injection pipe is open to a flow passage between an outer peripheral portion of the low pressure stage runner chamber and an inside of a movable guide vane of the low pressure stage. Two-stage pump turbine. 3. The two-stage pump water turbine according to claim 1, wherein one end of the water injection pipe is open to one of a runner side pressure chamber and a runner back pressure chamber of the low pressure stage runner. 4. A return flow passage communicating between the high pressure stage flow passage and the low pressure stage flow passage, runners and movable guide vanes installed in each of the high pressure stage and the low pressure stage, a high pressure stage runner chamber, and In the exhaust operation method of a two-stage pump water turbine, which comprises an exhaust passage for a high pressure stage and an exhaust passage for a low pressure stage, which communicate with the outside of the low pressure stage runner chamber, the low pressure stage when the movable guide vanes of the low pressure stage are fully closed. And a second step of detecting that the flow path between the outer peripheral portion of the low-pressure stage runner and the movable guide vane of the low-pressure stage is filled with the water. A third step of exhausting the air in the high-pressure stage runner chamber after the detection through the high-pressure stage exhaust passage, and the exhaust pipe and the high-pressure stage runner chamber in association with the exhaust of the third step. The high-pressure stage water supply pipe communicating with A fourth step of introducing water in the low pressure stage runner chamber into the high pressure stage runner chamber, and after the fourth step, air in the low pressure stage runner chamber is exhausted through the low pressure stage exhaust passage to remove water in the suction pipe. For introducing into the low pressure stage runner chamber
And the sixth step of slightly opening the movable guide vane of the low pressure stage after the fifth step and then closing the high pressure stage feed pipe. Exhaust driving method. 5. A return flow passage that connects the high pressure stage flow passage and the low pressure stage flow passage, runners and movable guide vanes installed in each of the high pressure stage and the low pressure stage, and from a water surface pushing idle operation. An exhaust passage for the high-pressure stage and an exhaust passage for the low-pressure stage that communicate the high-pressure stage runner chamber and the low-pressure stage runner chamber to the outside during the exhaust operation that shifts to normal operation, respectively, and the suction pipe and the return passage during the exhaust operation. Installed in the side pressure chamber or back pressure chamber of the high pressure stage runner and the high pressure stage runner chamber to reach the cutoff water pressure due to completion of filling. High pressure stage water pressure detecting means for detecting that the low pressure stage runner chamber is installed in the side pressure chamber or the back pressure chamber of the low pressure stage runner and for detecting that the low pressure stage runner chamber has reached the cutoff water pressure due to completion of filling of water. When,
A two-stage pump turbine, comprising: a control device that stops the main engine when the low-pressure stage water pressure detection means detects the deadline water pressure before the high-pressure stage water pressure detection means during the exhaust operation.